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Effects of temperature and fertilization on nitrogen cycling and community composition of an urban lawn
Author(s) -
BIJOOR NEETA S.,
CZIMCZIK CLAUDIA I.,
PATAKI DIANE E.,
BILLINGS SHARON A.
Publication year - 2008
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2008.01617.x
Subject(s) - cycling , lawn , fertilizer , nitrogen , agronomy , nitrous oxide , environmental science , soil water , biomass (ecology) , chemistry , botany , soil science , biology , archaeology , organic chemistry , history
We examined the influence of temperature and management practices on the nitrogen (N) cycling of turfgrass, the largest irrigated crop in the United States. We measured nitrous oxide (N 2 O) fluxes, and plant and soil N content and isotopic composition with a manipulative experiment of temperature and fertilizer application. Infrared lamps were used to increase surface temperature by 3.5±1.3 °C on average and control and heated plots were split into high and low fertilizer treatments. The N 2 O fluxes increased following fertilizer application and were also directly related to soil moisture. There was a positive effect of warming on N 2 O fluxes. Soils in the heated plots were enriched in nitrogen isotope ratio ( δ 15 N) relative to control plots, consistent with greater gaseous losses of N. For all treatments, C 4 plant C/N ratio was negatively correlated with plant δ 15 N, suggesting that low leaf N was associated with the use of isotopically depleted N sources such as mineralized organic matter. A significant and unexpected result was a large, rapid increase in the proportion of C 4 plants in the heated plots relative to control plots, as measured by the carbon isotope ratio ( δ 13 C) of total harvested aboveground biomass. The C 4 plant biomass was dominated by crabgrass, a common weed in C 3 fescue lawns. Our results suggest that an increase in temperature caused by climate change as well as the urban heat island effect may result in increases in N 2 O emissions from fertilized urban lawns. In addition, warming may exacerbate weed invasions, which may require more intensive management, e.g. herbicide application, to manage species composition.